Toxic algae in Wallkill could cause illness

The floating mats of the genus Microcystis can be seen by the Sojourner Truth Park in New Paltz. These algae can cause illness, particularly when ingested. People are warned to thoroughly wash themselves, their equipment and their dogs as soon as possible after any contact with this bloom. (Julie O’Connor | New Paltz Times)

Science may provide evidence that a particular river or stream has problems, but what people see with their own eyes can drive the point home. Think of the Cuyahoga River when it caught fire due to the chemicals in it, or the Esopus Creek which was turned the color of chocolate milk as a result of Ashokan Reservoir management practices. Add to that list the Wallkill River, which has turned bright green due to a toxic algae bloom.

Dan Shapley, water quality program manager at Riverkeeper, credits members of the Wallkill River Watershed Alliance for documenting this and other issues through kayak patrols. In a statement released jointly by leaders of the two organizations on August 25, the public was advised that, “The algae bloom was visible from bank to bank in the vicinity of New Paltz, including Sojourner Truth Park and at the Carmine Liberta (Route 299) Bridge reconstruction site. It has been visible as far upstream as Gardiner and as far downstream as Rifton. Other public-access locations within this section include the Village of New Paltz boat launch on Springtown Road, the Wallkill River Valley Rail Trail bridge crossing, the DEC boat launch in Town of Rosendale, Perrine’s Bridge Park in Town of Esopus, and several informal access sites used by anglers.”

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These floating mats are part of the genus Microcystis, which can cause illness, particularly when ingested. Microcystis is one of three genera of freshwater cyanobacteria (also known as blue-green algae) that are being tracked widely as sources of harmful algal blooms. People are warned to steer clear of it, and to wash themselves and their equipment thoroughly as soon as possible after any contact. In areas with power boats the algae can become aerosolized and be inhaled, but on the Wallkill River the primary danger is posed to pets and any humans who opt to take a swim there. Dogs tend to lick their fur as they dry off, and in some cases have died due to the toxins in these algae.

John Gotto, a member of the alliance, was one of the scientists who confirmed the type of algae involved. He said that Microcystis is not an invasive species, but a local resident that has had its growth encouraged by changes in the river. A similar harmful algal bloom was identified last year at this time. Conditions that lead to algae blooms such as this include high temperatures, slow or stagnant water, and excess nutrients in the water from sewage (both treated and untreated), and runoff of fertilizers from farms and lawns. “It can be a number of factors, including elevated temperature, slow flow and an excess of nutrients,” Gotto explained.

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The green color should be fading before long, but that’s not the end of the problems. Gotto expects it won’t last more than a week or two at most, but as the algae start to die off, “It starts to use up oxygen, leading to fish kills” and other environmental damage. At any time of year, it’s possible for locations along the Wallkill to have more fecal bacteria present than is deemed safe for swimming; such locations are generally posted. Gotto said that neither of these issues would make it unsafe to enjoy the river by kayak or canoe.

This situation brings up the question of whether or not the Wallkill could be considered as a potential drinking source, now or in the future. Village trustee Don Kerr, who works in the water-treatment field, has supported setting up infrastructure to do just that, because he says it’s entirely possible to make the water safe and drinkable.

Gotto demurred on answering that question, saying that since he’s not a village resident, he considers it an internal matter. Wallkill River Watershed Alliance director Jason West, former mayor of the village of New Paltz for two nonconsecutive terms, did respond. “Anything can be treated. It’s just a matter of cost and effort,” West said. Alliance members “have not yet made a recommendation on it as a source. There’s been an issue of alternate supply for a long time, and the alliance won’t get involved in that discussion.”

What the group will do, he said, is advocate for better riparian buffers to screen out excess nutrients, and encourage people to take individual steps to halt climate change, which is likely raising the temperature of the river.

“We shouldn’t be wasting a river like the Wallkill by polluting it,” said Shapley. “To me, this white-green slime is a giant plea for help, a rallying cry for all of us to get going on these long-term protections.”